Bladder construction for pressure vessels



J. MERCIER 3,113,592

BLADDER CONSTRUCTION FOR PRESSURE VESSELS Dec. 10, 1963 2 Sheets-Shet 1Filed Jan. 12, 1960 INVENTOR. JEA N [Wk-Ease WY-M A TTO RNEYF.

Dec. 10, 1963 J. MERCIER 3,113,592

BLADDER CONSTRUCTION FOR PRESSURE VESSELS Filed Jan. 12, 1960 M8 /23 weMg m 2 Sheets-$heet 2 mmyrok. JEAN MERC/El? BY fia lm United StatesPatent Office Patented Dec. 10, 1963 3,113,592. BLADDER CONTRUCTION FGRPRESSURE VESSELS .l'ean Mercier, 1185 Park Ave, New York, FLY. Filedden. 12, 196i), Ser. No. 1,931 2 Claims. (Cl. 1383tl) This inventionrelates to the art of pressure vessels generally known as pressureaccumulators, and more particularly to the deformable partition orbladder used in such accumulators.

It is among the objects of the invention to provide a pressureaccumulator of relatively low cost, which may readily be fabricated andwhich will function without likelihood of break-down or rupture ofthedeformable partition or bladder therein.

Another object is to provide a deformable partition or bladder to beused as a separator between two fluids in a pressure accumulator, whichbladder has a relatively large open mouth to permit ready extractiontherefrom of the core used in the molding thereof and which may besecurely, yet releasably, retained in position in a pressureaccumulator, without likelihood of rupture or breakdown of the materialof the bladder adjacent its relatively large mouth.

According to the invention, the pressure accumulator is of the typehaving a relatively large opening or mouth and a port opposed to suchopening. The accumulator has means adjacent the mouth to mount theperiphery of a partition or bladder of resilient deformable materialwhich is positioned in the accumulator to intervene between the openingand the port. The periphery of the partition, which desirably isthickened, has a rigid annular supporting member secured thereto. Themouth of the accumulator is closed by means of a cover plate, the rigidannular supporting member spacing said cover plate from the mountingmeans for the periphery of the partition. The rigid annular member andthe periphery of the partition are conformed so that the elasticmaterial of the bladder will securely adhere thereto, without likelihoodof separation between the partition material and the rigid annularmember during use of the accumulator.

In the accompanying drawings in which is shown one or more of variouspossible embodiments of the several features of the invention,

FIG. 1 is a longitudinal sectional view of an accumulator according toone embodiment of the invention,

FIG. 2 is a fragmentary longitudinal sectional view of anotherembodiment of the invention,

FIG. 3 is a sectional view of the clamping means for the embodimentshown in FIG. 2 after the partition therein is replaced,

FIG. 4 is a fragmentary detail view of another embodiment of the annularsupporting member,

FIGS. 5 and 6 are views similar to FIG. 2 of other embodiments of theinvention,

FIGS. 7 and 8 are detail sectional views of other embodiments of theinvention, and

FIG. 9 is a view illustrating the principle of the invention.

This application is a continuation-in-part of copending applicationSerial No. 635,154, filed January 22, 1957, now US. Patent 2,959,194granted November 8, 1960.

Referring now to the drawings, as shown in FIG. 1 the pressureaccumulator comprises a container or pressure vessel 11 of strong rigidmaterial such as steel, capable of withstanding high pressures, saidcontainer being substantially spherical at one end as at 12 and open atits other end as at 13, said end 13 illustratively being 2 of reducedthickness to define an internal annular shoulder 14.

The end 12 of the container has an axial opening or port 15 in which ismounted a closure assembly (not shown) of any suitable type such as isshown in United States Patent No. 2,469,171, dated May 3, 1949, throughwhich a fluid under pressure, such as oil, may flow into and out of thecontainer 11.

Positioned in the container 11 is a deformable partition 51,illustratively a collapsible and expansible bladder, which desirably isof resilient material such as rubber or synthetic plastic of likephysical characteristics.

The bladder has a thickened rim 52 to which an annular supporting member53 is aflixed, preferably by being bonded thereto or molded therein asillustratively shown. The supporting member 53 is a flat ring of rigidmaterial such as steel, of outer diameter slightly less than that of theshoulder 14, and has its axis aligned with the longitudinal axis of thebladder 51 thereby normally lying in a horizontal plane as shown.

The supporting member or ring 53 is molded with the bladder so that theupper surface of the outer periphery 54 thereof has a relatively thinlayer 55 of bladder material thereon, which is also true of thecorresponding bottom surface of the ring 53 at the outer peripherythereof as shown at 55 and 57 respectively. The inner periphery of thering 53, which is embedded in the thickened rim 52 of the bladder, has arounded surface and the bladder material extends from the thin layer 55laterally to and beyond such rounded surface 58 in a layer 61 that is ofgreater thickness than the thin layer 55.

The inner surface 62 of the wall of the bladder extends substantiallyvertically downward in the illustrative embodiment shown from the inneredge 62 of the thickened layer 61, and the outer surface 63 of thebladder wall tapers inwardly from the outer edge of the lowermost thinlayer 56. If desired, the bladder may be conformed in conical shape toprovide for progressive engagement of the bladder with the container inthe manner shown in Patent Re. No. 23,437, dated December 4, 1951.

Means are provided to close the open end of the container 11 and toretain the bladder 51 and the supporting member 53 in position. To thisend, a cover plate 65 is provided, which has a substantially curvedcentral portion 66 with a port 67 therein and an annular flange 68 witha depending lip 69 at its outer periphery 71.

The overall diameter of the cover plate 65 is slightly less than theouter diameter of shoulder 14 as shown in FIG. 1, and the inner diameterof lip 69 is slightly less than the outer diameter of the thicker layer61.

Thus, when the bladder is positioned in the container ll, the layer 56beneath the ring 53 will seat on the shoulder 3.4, with the layer 57 onthe outer periphery of ring 53 against the wall portion 73 adjacent theshoulder 14.

With the bladder so mounted, it will hang downwardly in the container11. The cover plate 65, when positioned over the open end 13 of thecontainer, will have the undersurface of lip 69 against the thin layer55 and the flange 63 against the thickened layer 61.

The cover plate is securely retained in position by means of a retainingring 74, the side wall 75 of which is internally threaded to coact withcomplementary threads on the container 11. The top '76 of the retain ingring extends inwardly over the annular flange 68 so that when theretaining ring '74- is screwed downwardly the cover plate will beclamped against the supporting ring 53, which in turn will be clampedagainst shoulder 14. By reason of the resilient layers 55, 56, 57 and61, which will be compressed by such clamping action, a dependable sealwill be provided which will prevent leakage of gas or liquid from theend 13 of the container.

With the construction above described, when a valve (not shown)controlling the liquid outlet port 15 is opened, the bladder, which haspreviously been charged with gas under pressure and compressed by liquidforced into the container 11 through the port 15, will expand to forceliquid from the container.

It is well known that when an elastic member is bonded to a plateperpendicular to the direction of the stresses, the maximum fatigue islocated at the periphery, and that when elastic material, such as isused in the bladder, is molded or bonded to a rigid member, it tends tounstick first at the periphery, i.e., where the material is bonded to afiat surface. However, by reason of the rounded periphery 58 of thesupporting member, which provides a greater length for extension of thebladder material and hence reduction of stresses at the periphery, thebladder material will adhere securely to such rounded surface so thatwith repeated expansion and contraction of the bladder in use of theaccumulator the bladder and the supporting member will remain securelybonded together.

This is clearly shown in FIG. 9, where when an elastic member X isbonded to a flat plate AE and is subjected to tension Y, the point awill move to a and the point b will move to b. As a-a' is less than b-b(at the periphery), the material at the periphery of the elastic memberwill have been subjected to more stress or strain than the materialbetween the peripheries of the elastic member and will unstick as at c.This problem is solved by making the length of the material at theperiphery of the elastic member longer than its length between theperipheries so that the material at the periphery will not be subjectedto greater stress than the material between the peripheries.

The pressure accumulator shown in FIG. 2 is similar in many respects tothat shown in FIG. 1 and corresponding parts have the same referencenumerals primed.

The container 11' has an outlet port (not shown) identical to that shownin FIG. 1, and a collapsible and expansible bladder 51 is positioned insaid container.

The bladder 51' has a thickened rim 52' with an annular supportingmember 81 molded therein. The supporting member is desirably curvedupwardly adjacent its inner periphery as at 82, and such curved portionhas perforations 83 through which the material of the bladder will passduring the molding operation so that the supporting member will besecurely retained in position. The bladder material completely fills theconcavity 84 of the supporting member and desirably extends slightlybeyond a line between the extremities of such concavity. The innersurface 62 of the wall of the bladder extends substantially verticallydownwardly from near the inner periphery 85 of the supporting member andthe outer surface 63' of said wall tapers inwardly from the outerperiphery of the supporting member at its undersurface.

Desirably, the inner periphery 35 of the supporting member has a notch86 on which is seated the annular lateral flange 87 of reinforcingmember $8, illustratively an annulus of resilient sheet material. Theside wall 89 of the reinforcing member extends sightly below thesupporting member 81 and is reversely bent as at 91.

The bladder 51' with its associated supporting member is positioned inthe container 11', with the tapered portion of the bladder adjacent theouter periphery of the supporting member resting on the outwardly curvedportion 92 of the mouth of the container 11'.

To close the mouth of the container, a curved cover plate 65 isprovided, of diameter substantially equal to that of the supportingmember 81, the curvature of plate 65' being such that when the outerperiphery of plate 65 rests against the outer periphery of supportingmember 81, the inner periphery 85 of the supporting t member 81 will beadjacent the undersurface of the cover plate 65, thereby securelyretaining the reinforcing member 88 in position on notch 86.

To retain the cover plate in position, the mouth of the container isrolled over the top of the plate 65' as at 94. Thus, the resilientbladder material in the concavity of the supporting member, as well asthe material beneath such member, will be compressed to provide adependable seal.

In the event that the bladder has to be replaced, it is a relativelysimple matter to cut the rolled portion 94 of the container along theline xx. After the-bladder has been replaced, the cover plate may besecurely clamped in position by means of a pair of arcuate clampingrings 96 shown in FIG. 3. Each of the clamping rings 96 in cross sectionis substantially U-shaped, the opposed surface 9 7 of each of the legshaving an incline substantially equal to the incline of the top surfaceof the cover plate 65' and the lower surface of the curved portion 92 ofthe container.

When the clamping rings are positioned so that the legs thereof straddlethe cover plate and the curved portion of the container, and a belt 98,preferably of steel, encompassing the segments is tightened in anysuitable manner, the clamping segments will be moved inwardly so thatthe curved portions of the leg will cam the cover plate downwardly toeffect a tight seal.

By reason of the reinforcing member 88, which is of resilient material,as the bladder is compressed and contracts during operation of theequipment, it will abut against the reinforcing member, which willdeflect inwardly slightly. However, such reinforcing member will preventsharp bending of the bladder, that is, it will limit the angle which thebladder Wall may make with respect to the wall of the container, so thatfatigue of the bladder will be greatly reduced to increase its life. Thecurved supporting member 81 also provides a greater length for extensionof the bladder material at the region of bonding thereto of the bladdermaterial to provide for secure adherence as described with respect tothe embodiment shown in FIG. 1.

The embodiment shown in FIG. 4 is substantially identical to that shownin FIG. 2 except for the construction of the supporting member 81'.Thus, as is clearly shown in FIG. 4, the supporting member has a shapesubstantially conforming to the shape of the supporting member shown inFIG. 3, but the supporting member of FIG. 4 is corrugated to enhance thegripping action of the bladder material thereto during the moldingoperation,

The embodiment shown in FIG. 5 is also similar to that shown in FIG. 3,except for the supporting member and the upper end of the accumulatorcontainer.

Thus, the accumulator container 106 shown in FIG. 5 has the curvedportion 92., but does not have the rolled portion 94 to hold the coverplate in position, but utilizes the clamping rings 96' which areidentical to the clamping rings 96 shown in FIG. 3. The supportingmember 101 of the embodiment shown in FIG. 5 is an annulus of rigidmaterial such as steel, which is substantially L-shaped in crosssection. The supporting member 101 is molded in the thickened rim 102 ofbladder 103 so as to be axially aligned with the longitudinal axis ofthe bladder. The horizontal leg 1% of the supporting member MP1 isrounded at its inner periphery as at 105, which is slightly spaced fromthe inner surface 1% of the wall of the bladder 103, and such horizontalleg has a plurality of perforations 107 through which the bladdermaterial will pass during the molding operation, securely to retain thesupporting member in position in such thickened rim. The vertical'leg108 of the supporting member is at the outer periphery thereof and is ofouter diameter-substantially equal to the outer diameter of the curvedportion 92' of the container 1th). The bladder material extends upwardlyfrom the outer periphery of the horizontal leg 104 of the supportingmember 101 on its top surface at an angle corresponding to the slope ofthe inner surface of the cover plate 111, said bladder material on thetop surface of the horizontal leg being originally of thickness greaterthan the spacing between the horizontal leg 104 and the cover plate whenthe outer periphery of the latter is against the outer periphery of thehorizontal leg. Similarly, the bladder material beneath the horizontalleg, which is curved on its outer surface to conform substantially tothe curvature of the curved portion 92' of the container 100, also is ofthickness slightly greater than the distance between the undersurface ofthe horizontal leg and the curved portion of the container 100 when theleg 108 is resting against said curved portion.

As the result of such construction, when the cover plate 111 is clampedagainst the supporting member 101 and the latter clamped against thecurved portion 92 of the container, the bladder material on the top andbottom of the supporting member will be compressed to effect adependable seal.

The embodiment shown in FIG. 6 is similar in many respects to theembodiment shown in FIG. 5. In this embodiment the supporting member 101is also substantially L-shaped in cross section, but the leg 104'thereon is bent downwardly from the vertical leg 168' thereof to providespace for the bladder material between the leg 104' and the adjacentportion 115 of the cover plate 111' which is substantially horizontal.

The mouth of the accumulator container 1% in the embodiment of FIG. 6has an annular flange 116 on which the lower end of the vertical leg 198is positioned, and the side wall of the container rises from said flangeand is rolled over the periphery of the cover plate 111 to retain thebladder and cover plate in fixed position.

In both of the embodiments of FIGS. and 6, by reason of the roundedinner periphery of the leg 104, 104 of the supporting members thebladder material will re main securely bonded thereto as previouslydescribed.

In the embodiment shown in FIG. 7, the container 121 has an outwardlyflaring flange 122 to which is secured as by rivets 123 the periphery ofa cover plate 124. The bladder 125 shown in FIG. 7 has its inner surface126 extending substantially vertically downward from the inner edge 127of a rigid, annular supporting member 128, which has a flat bottomsurface 129 to which the rim of the bladder is bonded. The outer surface131 of the bladder 125 tapers inwardly from a point spaced from theperiphery 132 of the supporting member 128 to provide a greater lengthof bladder material at the exterior surface of the bladder than inwardlyof such exterior surface.

As shown in FIG. 7, the periphery of the supporting member 128 rests onthe flange 122 of the container and is clamped thereagainst by the coverplate 124, the portion of the container adjacent its flange being curvedas shown to conform to the taper of the bladder.

In the embodiment shown in FIG. 8, the container 133 has an annularflange 134 at its mouth, with an upstanding peripheral rim 135 which isinwardly bent as at 136 to clamp the periphery of a cover plate 137against a rigid, annular supporting member 138 seated on flange 134,said supporting member 138 desirably having annular seals 139 in its topand bottom surfaces.

The bladder 141 has a thickened rim 142 extending laterally outward andbonded as at 143 to the supporting member. The length of the bladdermaterial at the inner surface 144 of the bladder at its rim is longerthan at the outer surface thereof to provide at least at the interior ofthe bladder, a length of bladder material that will permit extensiongreater than would be permitted by the length of bladder materialoutwardly of the interior of the bladder.

It is to be noted that since the longer length of bladder material issubject to less stretching, it would be less permeable, so that escapeof gas through the partition, even after long periods of idleness, inthe extended position of the partition is greatly minimized.

In all cases in the embodiment shown, it is necessary that there be alength of bladder material at the rim of the partition which is bondedto the supporting member that is longer than the length of bladdermaterial either inwardly or outwardly of the longer length of bladdermaterial as the case may be.

By reason of the constructions above described, a core used in themolding of the bladders may readily be removed therefrom and thereinforcing members at the relatively large mouth of the bladders willpermit secure retention of the bladders in position in the container andprovide for long life of such bladders.

As many changes could be made in the above constructions and manyapparently widely different embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

l. A pressure vessel comprising a rigid hollow con tainer having anopening and an opposed port, a partition of resilient deformablematerial in said container, said partition having a peripheral rim andextending across the container and intervening between said opening andsaid port, an annular supporting member of rigid material having a flatsurface bonded to said partition at the rim thereof, whereby stress isproduced against the bonded surface in use of the pressure vessel, thelength of the partition material at least one of the wall surfaces ofthe partition adjacent the rim thereof being longer than the length ofthe partition material between the opposed wall surfaces of thepartition adjacent the rim thereof, whereby the stress of the bondedportion of the rim of the partition against the supporting member atsuch longer wall surface in use of the pressure vessel will be reduced,mounting means for the rim of the partition at the periphery of saidopening and extending substantially laterally outward from said openingto guide the portion of the partition adjacent its rim in use of thepressure vessel so as to maintain the direction of the stress of thepartition material intervening between the exterior surfaces of thepartition adjacent its rib, exerted against the bonding surface atsubstantially right angles thereto, a cover plate adapted to extend oversaid opening and means to retain said cover plate in closed positionwith respect to said opening, rigid annular supporting member spacingsaid cover plate from said mounting means.

2. The combination set forth in claim 1 in which the mouth of saidcontainer has an outwardly extending flange curved on its top surface atthe root end of the flange, said annular supporting member has a flatsurface resting on the portion of the flange outwardly of its curved topsurface, the curved surface of said flange guiding the portion of thepartition adjacent its rim, the inner surface of said partition adjacentits rim being flared to define the longer length of bladder material.

References Cited in the file of this patent UNITED STATES PATENTS1,885,457 Lord et al. Nov. 1, 1932 2,365,063 Downey Dec. 12, 19442,394,401 Overbeke Feb. 5, 1946 2,773,511 Mercier Dec. 11, 1956

1. A PRESSURE VESSEL COMPRISING A RIGID HOLLOW CONTAINER HAVING ANOPENING AND AN OPPOSED PORT, A PARTITION OF RESILIENT DEFORMABLEMATERIAL IN SAID CONTAINER, SAID PARTITION HAVING A PERIPHERAL RIM ANDEXTENDING ACROSS THE CONTAINER AND INTERVENING BETWEEN SAID OPENING ANDSAID PORT, AN ANNULAR SUPPORTING MEMBER OF RIGID MATERIAL HAVING A FLATSURFACE BONDED TO SAID PARTITION AT THE RIM THEREOF, WHEREBY STRESS ISPRODUCED AGAINST THE BONDED SURFACE IN USE OF THE PRESSURE VESSEL, THELENGTH OF THE PARTITION MATERIAL AT LEAST ONE OF THE WALL SURFACES OFTHE PARTITION ADJACENT THE RIM THEREOF BEING LONGER THAN THE LENGTH OFTHE PARTITION MATERIAL BETWEEN THE OPPOSED WALL SURFACES OF THEPARTITION ADJACENT THE RIM THEREOF, WHEREBY THE STRESS OF THE BONDEDPORTION OF THE RIM OF THE PARTITION AGAINST THE SUPPORTING MEMBER ATSUCH LONGER WALL SURFACE IN USE OF THE PRESSURE VESSEL WILL BE REDUCED,MOUNTING MEANS FOR THE RIM OF THE PARTITION AT THE PERIPHERY OF SAIDOPENING AND EXTENDING SUBSTANTIALLY LATERALLY OUTWARD FROM SAID OPENINGTO GUIDE THE PORTION OF THE PARTITION ADJACENT ITS RIM IN USE OF THEPRESSURE VESSEL SO AS TO MAINTAIN THE DIRECTION OF THE STRESS OF THEPARTITION MATERIAL INTERVENING BETWEEN THE EXTERIOR SURFACES OF THEPARTITION ADJACENT ITS RIB, EXERTED AGAINST THE BONDING SURFACE ATSUBSTANTIALLY RIGHT ANGLES THERETO, A COVER PLATE ADAPTED TO EXTEND OVERSAID OPENING AND MEANS TO RETAIN SAID COVER PLATE IN CLOSED POSITIONWITH RESPECT TO SAID OPENING, RIGID ANNULAR SUPPORTING MEMBER SPACINGSAID COVER PLATE FROM SAID MOUNTING MEANS.